 Starting or inrush current
Equipment power-up causes a travelling wave that may be up to 13 times stronger than the rated current, with time constants of 0.1 to 0.7 seconds.
This phenomenon is due to the magnetisation of the magnetic circuit, which produces a significant magnetising current.The asymmetry and peak value of the current are maximal when tripping takes place as the voltage passes zero, and when the residual flux density on the same phase is at its highest point.The current wave shape displays a large number of order 2 harmonic components.This phenomenon results from normal network operation; it should not, therefore, be treated as a fault by protection devices, whichshould not interfere with this transient state. |
Trihal cast resin transformers HV/LV and HV/HV
